This type of conventional image forming apparatus uses a photosensitive sheet of a strip shape coated with microcapsules containing leuco dye and light hardenable substance. After a latent image is formed on the photosensitive sheet through exposure, the photosensitive sheet and copy paper coated with developer, are superposed and pressed by pressure developing rollers. Consequently, the microcapsules of the parts on the photosensitive sheet the light did not irradiate which did not harden, burst and the desired image is formed on the copy paper by the leuco dye contained in the capsules.
The above-mentioned photosensitive sheet is wound on a core in a roll shape and made in the form of a photosensitive sheet cassette. The photosensitive sheet cassette is further stored in a carriage and may be installed and removed together with the carriage from the main body of the image forming apparatus.
When the photosensitive sheet cassette is replaced and loaded along with the carriage in the main body of the image forming apparatus, a leader sheet attached to the forefront of the photosensitive sheet, is wound through a loading mechanism on a winding shaft whereon the used photosensitive sheet will be wound. At this time, the above-mentioned leader sheet is sent into the transportation path of the photosensitive sheet by a transport roller, further passes the pressure developing rollers and a loading guide plate that guides the leader sheet, and reaches the winding shaft. After the leader sheet attained the winding shaft, the winding shaft keeps rotating for a predetermined period, and the leader sheet is wound on the winding shaft meanwhile. After the elapse of the predetermined period mentioned above, it is determined that the winding operation of the leader sheet is complete. In this state, the image forming operation may be performed.
On the other hand, during the image forming operation, the latent image formed through an exposure operation on the photosensitive sheet, is transferred on the copy paper by the pressure developing rollers. The copy paper is then guided in a prescribed transportation direction by a copy paper guide plate, mounted below the loading guide plate.
However, in the conventional structure described above, the loading guide plate mounted on the paper ejection side of the pressure developing rollers, is fixed. Thus, while the loading guide plate is located at a position where it is able to guide appropriately the leader sheet toward the winding shaft during the loading operation where the photosensitive sheet is wound around the winding shaft, there is a possibility that during the image forming operation after the loading operation is completed, it also sends the copy paper ejected from the pressure developing rollers, in the winding shaft direction.
Meanwhile, the conventional structure described above presents the inconvenience that making the interval between the loading guide plate and the copy paper guide plate a little wide in order to insure the transportation path of the copy paper, hinders the loading operation of the leader sheet.
Moreover, in the conventional structure mentioned above, after the leader sheet reached the winding shaft, the completion of the winding operation is determined in correspondence with the elapse of the predetermined rotation period of the winding shaft, and whether the winding operation really ended is not sensed. Accordingly, the conventional structure presents the disadvantage that the winding of the leader sheet is considered to be completed even when it is not and thus that the reliability of the apparatus is insufficient in this matter.
Furthermore, the conventional structure presents also the inconvenience that the copy paper gets jammed easily and that the presence of the loading guide plate on the paper ejection side of the pressure developing rollers, is a hindrance when the jam processing operation is performed, that is when the operator inserts his or her hand in the section involved and removes the jammed copy paper.